1. Technical Field
This invention generally relates to image recognition and more specifically to identifying and tracking an object from two-dimensional data pictorially representing said object.
2. Background Art
Three-dimensional objects need to be recognized and tracked for a variety of reasons, including, for example, target tracking for weapon systems, vehicle tracking for security, and hand-held object tracking for interfacing to a computer. Interfacing to a computer could be applied, for example, to game playing, tele-operation of a robotic device, or surgical tool tracking for interacting with a virtual reality simulation, etc.
Position and orientation of three-dimensional objects can be identified through several techniques, including magnetic tracking sensors, active radio frequency (RF) sensors, and vision sensors.
Vision sensors have the benefit of being passive, with no electromagnetic emission. Northern Digital Inc. provides an optical tracking system, called Optotrak. This system requires IREDs (infra-red emitting diodes) to be attached to the object that is tracked and strobed (turned off and on in a precisely controlled manner). It further requires the use of multiple sensors for triangulation. Advanced Realtime Tracking GmbH provides the ARTtrack2 system, which tracks rigidly connected markers. It does not identify or track unmodified objects. Optotrack and ARTtrack2 do not support identification and tracking of multiple objects using regular cameras through algorithms that can be automatically generated and parameterized using CAD model-objects. Optotrak and ARTtrack2 require the component being tracked to be specifically designed for that purpose. For example, Optotrack requires the object being tracked to actively emit signals.